1. Field of the Invention
The present invention relates to an improvement in a throttle valve of a diving respirator.
2. Description of the Prior Art
FIG. 1 is a view explaining a respirable gas supply passage of a conventional diving respirator. Reference numeral 1 denotes a gas passage through which a respirable gas, such as oxygen reduced in pressure to a predetermined value is supplied, 2 is a first gas pressure detecting gauge for detecting a gas pressure in said gas passage 1, 3 is a first throttle valve having an orifice, 4 is a second gas pressure detecting gauge for detecting a gas pressure reduced by said first throttle valve 3, 5 is a second throttle valve having an orifice, and 6 is a mouth piece unit to which the respirable gas reduced in pressure by said second throttle valve 5 is supplied.
In such diving respirator, the degree of reduction in pressure of gas reduced by said first throttle valve 3 is indicated as a pressure difference between the first and second gas pressure detecting gauges 2 and 4 in the normal state. In case that the orifice of the first throttle valve 3 is clogged up, the second gas pressure detecting gauge 4 shows zero pressure. In case that the orifice of the second throttle valve 5 is clogged up, the first and second gas pressure detecting gauges 2 and 4 show the same pressure. Accordingly, a diver can recognize the fact from the indications of said two gauges 2 and 4.
FIG. 2 is a sectional view of the throttle valve 3 or 5 of the conventional diving respirator, wherein reference numeral 7 is a cylindrical valve body having a center hole, 8 is a gas outlet communicated to said center hole and opened at opposite portions of an outer peripheral surface of the valve body 7, 9 is a gas inlet communicated to said center hole and opened at one end surface of the valve body 7, 10 is a lid mounted to the other end surface of the valve body 7, 11 is an orifice valve inserted into said center hole of the valve body 7, 12 is an orifice passing through the center portion of said orifice valve 11 and communicated to said gas outlet 8 at one end thereof and gas inlet 9 at the other end thereof, 13 is a compression spring inserted between said lid 10 and orifice valve 11, 14 is an elastic film made of a rubber or the like fitted to the outer peripheral surface of said valve body 7 so as to close both ends of said gas outlet 8 of the valve body 7, and 15 and 16 are O rings for hermetically seal. Said elastic cover serves as a non-return valve.
In such conventional throttle valve 3 or 5, when gas is supplied to the gas inlet 9 of the valve body 7 from the gas passage 1, the gas is passed through said orifice 12 of the orifice valve 11 and reduced in pressure and exhausted to the outside through the gas outlet 8 and a gap formed between the outer peripheral surface of the valve body 7 and the elastic film 14 against the resilient force of the elastic film 14.
As stated above, in order to detect the clog of the throttle valve 3 or 5, it is necessary to watch always indications of said two gas pressure detecting gauges 2 and 4 of the conventional diving respirator. However, such watching is very difficult for the general diver and it is very dangerous if the diver continues the diving without knowing the clog of the throttle valve.